Mitigation of polycyclic aromatic hydrocarbons during olive pomace oil refining: comparative evaluation of CaO and chitosan-based adsorbents.

Abstract

Polycyclic aromatic hydrocarbons (PAH4; the sum of four priority PAHs: benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene, and chrysene) represent serious food safety concerns in edible oils, particularly olive pomace oil (OPO), due to high-temperature processing steps involved in its production. This study evaluated PAH4 mitigation during refining using bleaching clay (BC), activated carbon (AC), and CaO-based adsorbents, including CaO and CaO/chitosan composites, within a laboratory-scale refining framework. Crude OPO contained PAH4 and benzo[a]pyrene (BaP) levels exceeding European Union limits (19.13 µg/kg and 5.27 µg/kg, respectively). Degumming and neutralisation resulted in limited reductions, whereas bleaching was identified as the critical step for PAH removal. BC reduced PAH4 to 9.72 µg/kg, approaching regulatory compliance, while AC reduced PAH4 to non-detectable levels. CaO and CaO/chitosan systems achieved approximately 50-53% PAH4 reduction, demonstrating measurable mitigation capacity, although their performance remained lower than that of AC. Method validation (R2 ≥ 0.997, recoveries 84-93%, LODs 0.022-0.090 µg/kg) confirmed the robustness of the analytical data. Overall, while AC remains the regulatory benchmark, CaO-based materials derived from waste seashells show promise as complementary adsorbents for PAH mitigation, supporting the development of more sustainable refining strategies for edible oils.